Furnace for heating rock drills and the like



' March 24. 1925. 1,531,214

D. S. ODONOVAN FURNACE FOR HEATING ROCK DRILLS AND THE LIKE Filed Dec. 9, 1922 2 Sheets-Sheet l /6 xz T .9 l 12: 30 55 l0 .5? H 2 u 0 Z8 ix 2 20 iy iv J I In ra/51". Y 4 "51000170040 I I I 2 Patented Mar. 2 4, 1 92 5.

umrsn PATEN r errata.

DAVID STANISJLAU'S ponovm, or voeELroNrmN, TnAn'svA'AL, son'rn Arman, ASSIGN'OR TO otnon ovan manners LIMITED, or JoHAnnnsBuaG, some AFRICA. I c

' mmcmonmmm nocx nRrLLsAnn THE LIKE.

amide-mm fi ieafmecmber 9, 1922. Serial no. 605,926.

To a'ZZ w-Iwm it may concern:

Be it known that DAVID.

OZDQNovAN, a British-subject, :resid1ng int 12 Plantation, Vogel fontein, Transvaal Province, vUnion of South akfrica, has in-r vented ic'ertain new and useful Improvements in Furnaces for I Ieating Rook Drills and the Ilike, of which the following is a specifica'tion.v 7

The present invention :"has ireference to furnaces i'n'tend'ed especially 51:01 lheating rock drills for the purpose of eitherwforging or hardeningthem. J The invention is illustrated in %the accompanying drawings in which 4 Fig. I is a side elevat-ion ofra furnace for heating :rock drills preparatory to hardening them. 1 7

Fig. II is a. longitudinal section thereof on A A Fig. III.

Fig. III :is an end on BB Fig. sII, r

Fig'IV is aulongit'udinal sectionof a furnace for heating drills for forging.

Fig. Vie an enlarged cross section thereof, on C-'C Fig. IV.

In the drawings 2 iindicatesithe furnace structure in which is a grate-S, combustionechamber 4, =and:a muflle heating flue 5.

view partly sectioned From the latter the gases pass through a .7

down flue 6 and an ieconomizer chamber 7 to the chimney 8.

The drills 9, orother articles to be heated, are inserted i'nanufiles 110. Theseare tubular members. closed at their innerendsfll and open at the end 12 for the reception of the drills. Their inner endsproject into the furnace cavity and they are preferably arrangedhorizontally. In order to faicilitate', their renewal they are placed in sockets l3wliich may be cast integral with the plate 14, and are secured therein by asbestos packing 15 compressed by a gland They are spaced apart along the flue 5 so that their temperatures are progressively higher the nearer they are to the fire. In the case of the'hardening furnace, Figs. I to III,

two final heating "mufiles 10 are shown, disposed in the combustion chamber 4. .There are two corresponding rows of soaking lnuflles 10 in the heating flue 5, each row 1ntended to co-operate Withone final tube 1O and the rows being staggered. to assist the even distribution of heat. This furnace is STAmsLnns arranged to be Worked from one side and is s'shov'vnas provided with the automatic drill removing device 17 which is described in any1other application filed herewith.

The furnaceshown in FigsIV and W is for heating the drills for sharpening. It is de'sighedto be Worked from :both sides, the :mufiles 10 :being double ended and arranged in a singleirow. i

In each case the last muffle in :the flue .5 is provided withfa .pocket 18 for a pyrometer, which indicates on a conveniently p-laceddial19.,

The economlzer consists of a chamber 7 through which'the partiallycooled gases ;pass on their way to the uptake 8,.and-a *niunber OfihllbGS .20 with closedzends projecting into said chamber. These tubes are preferably arranged vertically.

The method ;of operation is that the cold drills are ;placed in the r-economizer tubes 20 v and arelthere preliminarily warmed. They are then placed in the coolest of the-soaking muflles l0 and after remaining there ;for a period are moved to the next hotter mufile and so on in SUCGQSSlOll llllllll [they attain the desired final temperature in the most highly heated mufile-and are removed from the furnace.

value in preventing internal strains in the metal; whilstthe tact thatthe drills are not exposed to the furnace, ases greatly assists in preventing deterioration of thequalityof the steel.

In order to maintain the desired tem ceive their increment of. heat in each of them in the same time and all be moved together.

It is preferred to use mechanical means for effecting the shifting of the drills through the series of muflles. For this purthe drills can This gradual-heating is of considerable pose there is provided a carriage 21- mounted to travel on rails 22 towards and from the furnace structure 2. It 1s so moved by a lever 28 fixed on a shaft 24 carried in fixed bearings 25. On said shaft is a toothed quadrant 26 which engages a pinion 27 secured on the axle 28 which also has the carriage wheels 29 fixed to it.

Mounted on the carriage 21 is a chain or other convenient conveyor 30. On said conveyor are fixed drill supports 31 spaced from one another in the direction of the conveyors length, by a distance equal to the distance between the muliies 10. The conveyor is moved step by step, through the same distance, by the lever pivoted to the conveyor frame and fitted. with a pawl 35 engaging the ratchet wheel 86 on the drum shaft 3 1 of the conveyor.

In making use of this mechanism, drills placed on the supports 31 are held thereby in position in the several muffles. \V hen the drill in the last or most highly heated mullie has attained the correct temperature, the lever 23 is actuated to retract the carriage 2i from the furnace, whereby all the drills are withdrawn from the muliles.

The finished drill is removed from its supports; the lever 32 is actuated to advance all the drills one step ahead, and a drill which has been taken from the economizer is placed on the unoccupied support thus brought into position; where'upon the lever 23 is brought back to its original position, thus returning the drills to the muflies, but all moved one muffle ahead.

I claim: 1. A furnace for heating drills and the like comprising a horizontal flue and a series of open ended muflies arranged substantially in a horizontal line and extending into the flue, the flue being of considerable length so that there is a wide range of temperature througho'ut the series of muflies.

2. A furnace for heating drills and the like, comprising a long horizontal flue, a series of open ended mutlles arranged in a substantially horizontal line and extending into the flue and supporting means arrangedcin line with the muflies and adapted to support a n'umber of drills with their ends in the muflles.

3. A furnace for heating drills and the like comprising a furnace structure providing a combustion chamber and a flue decreasing in cross sectional area away from the combustion chamber, and mulfles open at one end and positioned transversely in the flue at different points in the length thereof.

l. A furnace for heating drills and the like comprising a furnace structure providing a combustion chamber, a Hire, and an economizer chamber, a number of open ended mufiles disposed along the flue to be heated to different temperatures and a number of open ended tubes inserted into the economizer chamber.

5. A furnace for heating drills and the like comprising a furnacestructure, a row of muflies extending thereinto and arranged to be progressively heated to different temperatures and movable means for supporting drills or the like in the muliles, said means operating to advance the drills by steps from mufl'le to mul'fle.

6. A furnace for heating drills and the like comprising a furnace, a row of muflles therein presenting open ends externally to the furnace, a carriage retractible from the furnace structure, a conveyor mounted on the carriage to move parallel with the line ofmuflies, supports for the drills or the like on the conveyor and spaced equally with the muffles, and means for reciprocating the carriage to and from the furnace structure and to advance the conveyor step by step.

In testimony whereof I aflix my signature.

DAVID STANlSLAUS O'DONOVAN. 

